• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 41
  • 16
  • 6
  • 5
  • 4
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 96
  • 96
  • 11
  • 11
  • 10
  • 10
  • 10
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Imunoexpressão dos marcadores de apoptose em tumores epiteliais de anexos oculares de cães /

Lopes, Rodrigo Antonio. January 2012 (has links)
Orientador: Cláudia Valéria Seullner Brandão / Coorientador: Alexandre Lima de Andrade / Banca: Aparecida Pires de Campos Zuccari / Banca: Cláudia Helena Pellizzon / Banca: José Joaquim Titton Ranzani / Banca: Renné Laufer Amorim / Resumo: O presente trabalho tem por objetivos identificar a expressão dos genes supressores de tumor TP53 e p63, dos genes Bax e PUMA e dos marcadores da apoptose Caspase-2, Caspase-3, Bcl-2 e Anexina-V em tumores de anexos oculares espontâneos em cães. Foram utilizadas 20 casos de tumores dos anexos oculares no período de 1998 a 2009 de dois arquivos dos Serviços de Patologia Veterinária da UNESP campus de Araçatuba, e UNESP campus de Jaboticabal.Os cortes foram obtidos a partir dos blocos de parafina e submetidos à análise anatomopatológica e imunoistoquímica. Do total de 20 amostras foram diagnosticados 13 casos de carcinoma de células escamosas, 3 casos de carcinoma sebáceo, 2 caso de carcinoma basocelular e 2 casos de adenoma sebáceo. Todos as amostras apresentaram imunomarcação para as proteínas TP53 e p63, caspase 2, Bcl2, e Bax. Nas amostras com diagnóstico de neoplasia maligna com melhor diferenciação a imunomarcação é mais acentuada para estes marcadores os marcadores / Abstract: This aim of this study is to identify the expression of the tumor suppressor genes TP53 and p63, genes Bax and PUMA and apoptosis markers Caspase-2, Caspase-3, Bcl-2 and Annexin-V in spontaneous tumors in ocular adnexa dogs. 20 cases of tumors of the ocular adnexa in the period 1998 to 2009 were used of two files of the Veterinary Pathology of UNESP campus Araçatuba and UNESP campus Jaboticabal. The sections were obtained from the paraffin embedded and subjected to histopathological analysis and immunohistochemistry. From those 20 samples, were diagnosed 13 cases of squamous cell carcinoma, 3 cases of sebaceous carcinoma, 2 cases of basal cell carcinoma and 2 cases of sebaceous adenoma. All samples showed immunostaining for proteins P53 and P63, caspase 2, Bcl2, and Bax. In samples with a diagnosis of malignancy with better differentiation is more pronounced immunostaining for these markers markers / Doutor
62

Differential Diagnosis of Pan-Uveitis: Behçet’s Disease

Blosser, Peter, Simon, Remil, Ridner, Courtney 05 April 2018 (has links)
This report describes the case of a 56-year-old man who presented with blurry vision, increased intraocular pressure, and conjunctival injection after posterior chamber intraocular lens implantation. Initially post-operative endophalmitis and foreign body inflammation were considered as differential diagnoses, but after further examination pan-uveitis was diagnosed. Uveitis is an ocular finding that may indicate several diseases, one of which is Behçet’s Disease. During the interview, the patient mentioned a history of apthous ulcers and genital ulcers which then lead to the clinical diagnosis of Behçet’s Disease. This report emphasizes that Behçet’s Disease is rare in Caucasians. Therefore, is frequently misdiagnosed in North America due to variable presentations and by not exploring the option when analyzing differential diagnoses. Early diagnosis and intervention will prevent the development of blindness and fatality due to complications of the disease.
63

Biometrický systém pro rozpoznávání podle sítnice a duhovky oka / Biometric system for retina and iris recognition

Hájek, Josef Unknown Date (has links)
Tato disertační práce se zabývá biometrickým a medicínským zařízením pro simultánní snímání duhovky a sítnice oka v jednom kroku. V případě biometrického zaměření je práce rozšířena o vzájemnou fúzi těchto dvou biometrik do jedné šablony, kdy multimodální systém vykazuje mnohem lepší parametry než systém unimodální, a to především ve větší unikátnosti, univerzálnosti a velmi obtížně proveditelnému útoku (až téměř nemožnému) na senzor. V případě medicínského využití práce dále rozvíjí detekci a klasifikaci nemocí pro základ expertního systému pro oftalmologické účely, který bude umožňovat pomoc lékaři při stanovení diagnózy nálezu v obrazu sítnice (či duhovky) oka.
64

Employing mHealth Applications for the Self-Assessment of Selected Eye Functions and Prediction of Chronic Major Eye Diseases among the Aging Population

Abdualiyeva, Gulnara 24 May 2019 (has links)
In the epoch of advanced mHealth (mobile health) use in ophthalmology, there is a scientific call for regulating the validity and reliability of eye-related apps. For a positive health outcome that works towards enhancing mobile-application guided diagnosis in joint decision-making between eye specialists and individuals, the aging population should be provided with a reliable and valid tool for assessment of their eye status outside the physician office. This interdisciplinary study aims to determine through hypothesis testing validity and reliability of a limited set of five mHealth apps (mHAs ) and through binary logistic regression the prediction possibilities of investigated apps to exclude the four major eye diseases in the particular demographic population. The study showed that 189 aging adults (45- 86 years old) who did complete the mHAs’ tests were able to produce reliable results of selected eye function tests through four out of five mHAs measuring visual acuity, contrast sensitivity, red desaturation, visual field and Amsler grid in comparison with a “gold standard” - comprehensive eye examination. Also, part of the participants was surveyed for assessing the Quality of Experience on mobile apps. Understanding of current reliability of existing eye-related mHAs will lead to the creation of ideal mobile application’ self-assessment protocol predicting the timely need for clinical assessment and treatment of age-related macular degeneration, diabetic retinopathy, glaucoma and cataract. Detecting the level of eye function impairments by mHAs is cost-effective and can contribute to research methodology in eye diseases’ prediction by expanding the system of clear criteria specially created for mobile applications and provide returning significant value in preventive ophthalmology.
65

Elucidating endothelial Caspase-9 signaling pathways in retinal vein occlusion

Potenski, Anna Michelle January 2022 (has links)
Central nervous system (CNS) tissues are highly metabolically active which makes them particularly susceptible to vascular injury. Disruption to the supply of oxygen and nutrients by damaged vasculature can result in neurodegeneration in both the eye and brain. The retina is an accessible part of the CNS that can be taken advantage of to study neurovascular diseases through live, non-invasive visualization of vascular and neuronal conditions upon injury. Retinal vein occlusion (RVO) is a common neurovascular disease of the eye and is the second leading cause of blindness in working age adults. While pathophysiology is well described and can be determined by retinal edema, breakdown of the blood-retina-barrier (BRB), inflammation, and neurodegeneration, the underlying signaling pathways behind the pathology is not well understood. To understand the mechanism of disease in RVO, the Troy lab has employed a mouse model to investigate pathways. Previous studies in the lab determined that as early as 1 hour post RVO, there was a large induction of caspase-9, a known cell death protease, in endothelial cells. When further investigated, it was confirmed that these cells were not dying despite the high expression of caspase-9, implying a non-apoptotic role. Deletion of endothelial caspase-9 was sufficient to protect against the development of retinal edema, capillary ischemia, and neuronal death, indicating caspase-9 is a key player in the mechanism of disease. This thesis work aims to investigate which signaling events drive non-apoptotic endothelial caspase-9 signaling by investigating upstream and downstream mechanisms of endothelial caspase-9. To interrogate this question, the mouse model of RVO was optimized, limiting the variability previously observed to ensure accurate and reproducible results. Then, we used a tamoxifen inducible endothelial cell Apaf-1 (apoptosis protease activating factor-1) knock out (Apaf-1 iECKO) mouse line in order to investigate the contribution of upstream activation of non-apoptotic endothelial caspase-9 signaling. Apaf-1 iECKO mice and WT littermates were subjected to RVO. Then, expression of caspase-9 and -7, retinal edema, capillary ischemia, neuronal death, vision dysfunction, and BRB integrity were measured. The deletion of endothelial Apaf-1 resulted in reduced expression of cl-caspase-9 and caspase-7, indicating endothelial caspase-9 was activated by Apaf-1. Apaf-1 deletion also resulted in protection against some of the pathologies seen after RVO including retinal edema, capillary ischemia, and neurodegeneration. Lastly, in order to elucidate the signaling pathway further, experiments using endothelial cell-specific AAVs (adeno-associated virus) packaged with a downstream caspase-7 inhibitor were proposed and described. In sum, this thesis work reveals that endothelial caspase-9 is canonically activated by Apaf-1, but still leads to non-apoptotic signaling, indicating downstream caspase-9 substrates could be the source for non-apoptotic function within endothelial cells.
66

The Role of Sox4 in Regulating Choroid Fissure Closure and Retinal Neurogenesis

Wen, Wen 01 January 2016 (has links)
The development of the vertebrate eye is tightly controlled by precise genetic regulations. From a single ocular primordium to bilateral eyes with complex structures and cell types, it requires intensive proliferation and migration for cells in both the ectoderm and mesoderm to accomplish ocular morphogenesis, and during this process cell differentiation and interaction takes place to establish the complex composition of ocular cell types and cellular connections. Genetic defects can lead to severe abnormalities in eye morphogenesis and cell differentiation during ocular development. A tremendous amount of work has been done to identify both intrinsic and extrinsic factors that regulate ocular development. However, much more work is needed to fully understand this complex process. Sox4 is known as a transcription activator that regulates cell survival and differentiation in multiple embryonic tissues during development. Evidence of its requirement during ocular development has recently emerged, but the mechanism by which Sox4 regulates ocular development is far from elucidated. Chapter 1 of this dissertation provides an overview of different stages in embryonic eye development and known genetic interactions during each stage. It also reviews recent knowledge about SoxC proteins and their roles in ocular development. Chapter 2 presents data characterizing the expression profile of the zebrafish sox4 co-orthologs, sox4a and sox4b, in the developing eye. Additionally, it presents data from morpholino-mediated sox4 knockdown in zebrafish, which indicate that Sox4 deficiency leads to defects in choroid fissure closure through elevation in the Hedgehog (Hh) signaling pathway. Sox4 knockdown causes upregulation of the Hh ligand indian hedgehog b (ihhb), which alters the proximal-distal boundary of the optic vesicle and inhibits choroid fissure closure. Chapter 3 presents data reporting the generation of sox4 mutant zebrafish lines using the CRISPR/Cas9 genome editing system. Characterization of one sox4a maternal zygotic (MZ) mutant line confirms Sox4’s role in negative regulation of Hh signaling and reveals new evidence that maternal and zygotic sox4 are both critical for ocular development. Chapter 4 presents data demonstrating that sox4 is required for rod photoreceptor neurogenesis. Rod photoreceptor terminal differentiation is delayed in both sox4 morphants and sox4 CRISPR mutants, while rod progenitor and precursor cells are properly specified. In Chapter 5, the roles of Sox4 in regulating ocular development are summarized based on the results, and implications of the results are discussed to expand our understanding of the genetic regulation of ocular morphogenesis and retinal neurogenesis.
67

Nutrition et dégénérescence maculaire liée a l’âge : approche épidémiologique du rôle des lipides / Nutrition and age macular degeneration : role of lipids with an epidemiological approach

Merle, Benedicte 17 December 2012 (has links)
La dégénérescence maculaire liée à l’âge (DMLA) représente actuellement la principale cause de cécité dans les pays industrialisés. Les traitements disponibles ne concernent qu’une partie des cas (DMLA néovasculaire) et n’évitent pas toujours le développement de déficiences visuelles sévères. L’identification de facteurs modifiables, tels que la nutrition, pourrait représenter des moyens de prévention permettant de diminuer la fréquence de cette maladie handicapante dans nos populations. L’objectif de la thèse était d’étudier d’un point de vue épidémiologique, la relation entre nutrition et DMLA chez les 963 sujets de l’étude Aliénor (Antioxydants Lipides Essentiels Nutrition et maladies OculaiRes), âgés de 73 ans et plus, avec un intérêt particulier pour les lipides. La relation entre les lipides et la DMLA repose principalement sur la potentielle implication du métabolisme lipidique dans la physiopathologie de la DMLA, ainsi que sur le triple rôle structurel, fonctionnel et protecteur des acides gras polyinsaturés (AGPI) n-3 au sein de la rétine. Dans un premier temps, nous avons mis en évidence une diminution du risque de DMLA chez les sujets ayant des apports alimentaires élevés en AGPI n-3. L’estimation des apports alimentaires étant sujette à de nombreuses imperfections (déclaration des sujets, biais de mémorisation, imprécisions des tables de composition alimentaire…), nous avons ensuite utilisé un biomarqueur du statut en AGPI n-3 afin de s’affranchir de ces limites. Ce travail nous a permis de mettre en évidence une diminution du risque de DMLA prévalente et incidente chez les sujets ayant des niveaux plasmatiques élevés d’AGPI n-3. Enfin, nous avons étudié les relations de certains gènes impliqués dans le métabolisme lipidique avec DMLA, les niveaux de lipides sanguins et de xanthophylles. Il ressort que les sujets TT pour le polymorphisme du gène LIPC (rs493258) présentaient un risque diminué de DMLA ainsi que des niveaux plasmatiques de zéaxanthine plus élevés. Ces travaux viennent compléter et enrichir la littérature à ce sujet et apportent des arguments nouveaux quant au rôle des AGPI n-3 dans la rétine ; ils pourront également servir de support en matière de recommandations nutritionnelles et de prévention de la DMLA. Nos travaux sur l’implication des gènes du métabolisme des lipides soulèvent de nouvelles questions quant aux mécanismes impliqués dans cette pathologie et pourraient suggérer de nouvelles pistes de recherche thérapeutiques et préventives. / Age-related macular degeneration (AMD) is the leading cause of blindness in industrialized countries. Current treatments are limited to the neovascular form of the disease only and do not always prevent the development of severe visual impairment. The identification of modifiable risk factors, such as nutrition, may lead to preventive strategies, which may have the potential to reduce the impact and burden of AMD on the global aging population. The objective of the thesis was to study the association between nutrition and AMD in the 963 subjects, aged 73 years or older, from the Alienor Study, with a particular emphasis on lipids. The relationship between lipids and AMD is primarily based on the potential involvement of lipid metabolism in the pathogenesis of AMD and on the structural, functional and protective roles of omega-3 polyunsaturated fatty acids (PUFAs) in the retina. First, we showed that high intakes of omega 3 PUFAs were associated with a decreased risk for AMD. Estimation of dietary intakes being affected by many imperfections (bias in reporting, memory bias, inaccuracies from food composition tables...); we used an omega 3 PUFAs biomarker in order to overcome these limitations. This second work showed that high plasma levels of omega 3 PUFAs were associated with a decreased risk for prevalent and incident AMD. Finally, we studied the associations of genes involved in lipid metabolism with AMD, plasma lipids and xanthophylls. It appears that subjects bearing TT genotype for LIPC gene had a decreased risk of AMD and higher plasma levels of zeaxanthin. These results provide new arguments about the role of omega-3 PUFAs in the retina. They can also provide support and recommendations for prevention of AMD. This work on genes involved in lipid metabolism suggest new questions about mechanisms involved in AMD and may suggest new way of research in treatment and prevention.
68

Saúde ocular na população indígena Kadiwéu do Mato Grosso do Sul / Eye health among Kadiwéu Indians of Mato Grosso do Sul-Brazil

Salum, Tania Gisela Biberg 13 April 2012 (has links)
OBJETIVO: O perfil epidemiológico dos povos indígenas no Brasil ainda não é suficientemente conhecido, principalmente no que se refere aos aspectos oftalmológicos das etnias residentes na região Centro-Oeste. Sendo assim, o objetivo do presente estudo foi conhecer as condições de saúde ocular da população indígena Kadiwéu, que habita as aldeias da serra Bodoquena, no Mato Grosso do Sul. MÉTODO: Foi conduzida uma pesquisa observacional, transversal e descritiva, desenvolvida na Aldeia Alves de Barros, na Serra da Bodoquena, no município de Porto Murtinho, Mato Grosso do Sul. Foram sujeitos da pesquisa 193 índios de um total estimado de 1.197. RESULTADOS: Da amostra avaliada, 74,9% apresentaram acuidade visual maior ou igual a 0,8. Dentre as ametropias, a hipermetropia foi o achado mais comum (9,3%) e a miopia o menos comum (2%). Dentre os achados da conjuntiva, a melanose e o pterígio foram os mais frequentes, com porcentagens de 25,4 e 14,7, respectivamente; em relação à avaliação das pálpebras, o achado mais comum foi a dermatocálase, com frequência de 4,5%. Quanto à córnea, encontraram-se casos de leucoma (n=4) relacionados a trauma ocular e uma suspeita de ceratocone; opacificação de cristalino foi observada em 5,6% dos indígenas avaliados e um caso de coloboma de íris foi verificado. Apenas um dos avaliados apresentou estrabismo convergente e um estrabismo divergente e não foram observados casos de hipertensão ocular ou glaucoma. Nenhum caso de discromatopsia foi encontrado. CONCLUSÃO: Pode-se concluir que os indígenas desta etnia apresentam, na sua maioria, boas condições oculares, com acuidade visual >=0,8, tendo apresentado, como alterações mais comuns, melanose da conjuntiva, pterígio, opacificação do cristalino, dermatocalaze e sequelas de traumatismos. A hipermetropia foi a ametropia mais comum (9,3%) e a miopia a menos comum (2%) / PURPOSE: The epidemiological profile of indigenous population in Brazil still remains insuffiently known.Considering ethnic groups living in the Center-West region of Brazil a limited number of reports is available regarding their ocular aspects. Based on these facts this study was conducted to elucidate the ocular conditions of Kadiwéus population, a specific ethnic group living in Bodoquena\'s Mountains in the state of Mato Grosso do Sul. METHODS: This is a crosssectional, descriptive and observational study performed with 193 Kadiwéus indians of a total of 1197 residents in the small villages in Bodoquena\'s Mountains. RESULTS: Of the selected sample, 74,9% had visual acuity better than 0.8. Among the refractive errors, hypermetropia was the most common (9,3%) and miopia the less frequent (2%). Melanosis and pterigyum are the conjunctiva most frequent findings, with percentages of 25,4 and 14,7 respectively; dermatochalasis had a frequency of 4,5%. Among corneal detected alterations, corneal clouding related to trauma was the most frequent and, one case of suspected keratoconus was found. Cataract was observed in 5,6% of the sample and one case of iris coloboma was verified. One case of convergent strabismus and one case of divergent strabismus were found. Ocular hypertension, glaucoma or dyschromatopsias were not verified. CONCLUSIONS: This study concluded that the Kadiwéus presented good ocular conditions, with visual acuity better than 0.8, in which, melanosis, pterigyum, cataract, dermatochalasis, trauma sequelae were the most frequent findings and hyperopia was the most common refractive error (9,3%)
69

Developmental and Protective Mechanisms of the Ocular Lens.

Unknown Date (has links)
The vertebrate eye lens functions to focus light onto the retina to produce vision. The lens is composed of an anterior monolayer of cuboidal epithelial cells that overlie a core of organelle free fiber cells. The lens develops and grows throughout life by the successive layering of lens fiber cells via their differentiation from lens epithelial cells. Lens developmental defect and damage to the lens are associated with cataract formation, an opacity of the lens that is a leading cause of visual impairment worldwide. The only treatment to date for cataract is by surgery. Elucidating those molecules and mechanisms that regulate the development and lifelong protection of the lens is critical toward the development of future therapies to prevent or treat cataract. To determine those molecules and mechanisms that may be important for these lens requirements we employed high-throughput RNA sequencing of microdissected differentiation statespecific lens cells to identify an extensive range of transcripts encoding proteins expressed by these functionally distinct cell types. Using this data, we identified differentiation state-specific molecules that regulate mitochondrial populations between lens epithelial cells that require the maintenance of a functional population of mitochondria and lens fiber cells that must eliminate their mitochondria for their maturation. In addition, we discovered a novel mechanism for how lens epithelial cells clear apoptotic cell debris that could arise from damage to the lens and found that UVlight likely compromises this system. Moreover, the data herein provide a framework to determine novel lens cell differentiation state-specific mechanisms. Future studies are required to determine the requirements of the identified molecules and mechanisms during lens development, lens defense against damage, and cataract formation. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
70

Effects of ischemic preconditioning and postconditioning on retinal ganglion cell survival after injury. / 缺血性預處理和後處理在不同損傷中對視網膜節細胞存活的影響 / CUHK electronic theses & dissertations collection / Que xue xing yu chu li he hou chu li zai bu tong sun shang zhong dui shi wang mo jie xi bao cun huo de ying xiang

January 2012 (has links)
本研究採用結紮眼血管的方法誘發短暫性視網膜缺血,針對同缺血時間同存活時間化成年金黄地鼠中視網膜節細胞的存活和小型膠質細胞的激活。首先,我們的據顯示,和假缺血手術組相對應的存活時間比較,暫時性視網膜缺血10分鐘或30分鐘沒有導致視網膜節細胞的存活明顯下。暫時性視網膜缺血60分鐘再灌注後7天,視網膜節細胞的存活下至58%,14後為51%,28後為44%。暫時性視網膜缺血120分鐘之後再灌注7天,視網膜節細胞的存活急劇下,僅保22%,至14天,僅剩17%, 之後節細胞的死亡速減緩,至28天時,仍由18%存活。視網膜缺血10分鐘、30分鐘、60分鐘和120分鐘均引起大小型膠質細胞激活,激活在第七天達到頂峰,之後在14天和28天顯著並逐步下。相關性分析發現損傷後7天,視網膜節細胞的死亡和視網膜節細胞層中的小型膠質細胞存在緊密的相關性。 / 其次,我們首次證實缺血性預處僅有於提高視網膜節細胞對抗視網膜缺血/再灌注損傷,還對視神經斷後的視網膜節細胞同樣具有保護作用。結果顯示無是5分鐘還是10分鐘的缺血性預處,無是軸突橫斷術前1天還是前3天實施預處,都對視網膜節細胞有明顯的保護作用。在缺血性預處對抗神經橫斷損傷的實驗組, 的表達只表現在陽性細胞上的明顯優勢,但占全部存活細胞的百分比存在差;而缺血性預處對抗視網膜缺血再灌注損傷的實驗組,的陽性節細胞的無論還是存活百分比都存在差。在預處組和假處組的比較中, 的表達也只是陽性細胞上較多,占全部存活細胞的百分比存在差。在缺血性預處加視網膜缺血分鐘的實驗組中,我們測視網膜矢片中各層的厚。結果顯示,缺血性預處組中,視網膜的整體厚和節細胞層的厚都與正常組相當,而假處組中,這層的厚明顯減少。 / 進一步地,我們研究遠端缺血性後處對視網膜節細胞對抗視神經軸突橫斷術的保護作用。我們選用鉗夾右股動脈作為遠端缺血性後處的方法,鉗夾股動脈分鐘,之後放開,再鉗夾再放開,共個循環。結果顯示,軸突橫斷術后分鐘實施缺血性后處組,視網膜節細胞的存活較假處組明顯增加,包括術後天和天;軸突橫斷術后小時實施缺血性後處組,視網膜節細胞的存活只在術後天較假處組明顯較多,但在天的實驗組,者的差消失;軸突橫斷術小時實施缺血性後處組,視網膜節細胞的存活比假處組多。在缺血性後處的實驗中,視神經橫斷術后分鐘實施遠端缺血性後處的實驗組與假處組比較,的表達僅表現在陽性細胞上的明顯增加,而且占全部存活細胞的百分比也明顯增加。的表達與預處實驗組的結果相似,只存在上的優勢。 / 我们的實驗證明,缺血性預處在對抗視神經橫斷和視網膜缺血的損傷中,可以為節細胞提供有效的保護作用,遠端缺血性後處可以對抗視神經橫斷損傷提高節細胞的存活。陽性節細胞在三個同條件的實驗中,表現出同的結果,这可能暗示遠端缺血性後處對抗視神經橫斷術的損傷,節細胞的再生能較優,與遠端缺血性後處對抗視神經橫斷術的神經保護作用有一定關。的表達在三個實驗組中,處組與假處組比較,均只表現出陽性細胞上的優勢,占存活細胞的百分比就存在差,可能意味著與缺血性預處和後處的保護作用關係不大。 / Ligature of the ophthalmic vessels (LOV) was used as an animal model to study transient retinal ischemia/reperfusion in adult hamsters. Firstly, we quantified the loss of retinal ganglion cells (RGCs) and activation of microglia after10 min, 30 min, 60 min or 120 min retinal ischemia at 7, 14 and 28 days post-ischemia. The results showed that after 10-min or 30-min retinal ischemia, the number of RGCs had no significant decrease compared to sham LOV group at 7 days. In the retinal ischemia 60 min group, there were 58% of the RGCs population remained alive at 7 days, 51% at 14 days and 44% at 28 days post-ischemia, respectively. In the retinal ischemia 120 min group, the number of RGCs was reduced to 22% at 7 days and 17% at 14 days, but cell death slowed down from 14 to 28 days. Meanwhile, the number of microglia was increased sharply at 7 days and decreased gradually from 7 to 28 days. At the same time, it was found that the loss of RGCs and activation of microglia in the ganglion cell layer at 7 days post-insult existed strong positive correlation. / Secondly, the effects of ischemic preconditioning (IPC) were proved to promote RGCs survival after axotomy or retinal ischemia 120 min. It was presented firstly that a 5 or 10 min brief IPC which performed 1 or 3 days prior to axotomy enhanced the RGCs survival at 7 days and 14 days post-axotomy. The number of HSP27-positive RGCs was significantly higher in the IPC plus axotomy subgroup compared with the sham-operated subgroup, while the percentage of HSP27-positive RGCs did not show significant difference between subgroups. For the IPC plus retinal ischemia 60 min group, both the number and the percentage of HSP27-positive RGCs had no significant difference between IPC and sham-operated subgroups. The number of HSP70-positive RGCs exhibited significant difference but not the percentage in IPC plus axotomy or retinal ischemia 60 min experimental groups. The thicknesses of the whole retina and GCL were similar to the normal value in the IPC plus ischemia 60 min subgroup, while in the sham-operated subgroup, these two values decreased significantly. / Consequently, the effect of remote ischemic postconditioning (RIPostC) was also explored to promote RGCs survival after axotomy. Four cycles of 10 min occlusion and 10 min release of the right femoral artery were initiated on animals at 10 min, 6 h or 24 h after axotomy. In the10 min group, the effect of RIPostC on promoting RGCs survival was significant at both 7 and 14 days post-injury. In the 6 h group, the survival of RGCs was more in the RIPostC treatment subgroup at 7 days, while there was no significant difference at 14 days post-axotomy. In the 24 h group, RGC survival was not significantly different at 7 days post-axotomy. Both the number and the percentage of HSP27-positive RGCs were significantly higher in the RIPostC treatment subgroup. The results of the induction of HSP70 only showed a priority in absolute number of the HSP70-positive RGCs in the RIPostC treatment subgroup. / In summary, the effect of IPC has been proved that it could protect RGCs against axotomy and retinal ischemia/reperfusion injury, in addition, the application of RIPostC also protected RGCs from axotomy. The proportion of HSP27-positive RGCs increased significantly in the process of RIPostC against axotomy, which may clue that the ability of axonal regeneration is stronger which induced by the RIPostC intervention. The upregulation of HSP27 might play a role in the neuroprotection of the RIPostC against axotomy. The expression of HSP70 maybe plays a little role in the neuroprotection of the IPC and RIPostC. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liu, Xia. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 182-196). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.i / Abstract in Chinese --- p.iv / Acknowledgements --- p.vii / Table of Abbreviations --- p.viii / Table of Contents --- p.ix / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter Chapter 2 --- Changes of retinal ganglion cells and microglia after different types of injuries / Introduction --- p.38 / Materials and Methods --- p.43 / Results --- p.49 / Discussion --- p.57 / Figures and tables --- p.71 / Chapter Chapter 3 --- Ischemic preconditioning protect retinal ganglion cells against axotomy and retinal ischemia/reperfusion injury and expression of heat shock protein 27 and 70 / Introduction --- p.93 / Materials and Methods --- p.98 / Results --- p.103 / Discussion --- p.109 / Figures and tables --- p.116 / Chapter Chapter 4 --- Remote ischemic postconditioning protect retinal ganglion cells against axotomy and expression of heat shock protein 27 and 70 / Introduction --- p.143 / Materials and Methods --- p.147 / Results --- p.150 / Discussion --- p.154 / Figures and tables --- p.161 / Chapter Chapter 5 --- General Discussion --- p.175 / References --- p.182

Page generated in 0.0475 seconds